Mary is right, treadle feeders are for full size birds. Anything under a couple of pounds is gonna have problems and either has to learn to eat from the side or the feeder has to be adjusted to accommodate them. Below a couple of pounds, treadle feeders can be dangerous so don't use them with tiny birds unless you are willing to take a small risk. Then again, there was a thread that I read on this very forum abut a UK flock owner who lost her entire flock thanks to stress caused by rats. Chickens already carry a ton of diseases that are kept in check by their immune system and the least bit of stress like moving them to a new location can trigger a disease. Pick your poison, not doing anything has risks too.